Ferrimagnetic spinel CoFe2O4 (CFO) films are integrated with Si(111) using Sc2O3 buffer layers. The huge lattice mismatch (17) between CFO and Sc2O3 is accommodated by domain matching, and CFO grows epitaxially with (111) out-of-plane orientation and coexistence of A- and B-type in-plane crystal variants. CFO films have low roughness of 4 and saturation magnetization of about 300 emu/cm3. These properties make CFO films on Sc 2O3-buffered Si(111) comparable to those grown on oxide single crystals and thus extend the possibilities of using spinel oxides in electronic devices. © 2011 American Institute of Physics.